Univention Corporate Server 4.3 erratum 351 (bugfix)

This update addresses the following issue(s):
* The scrolling in the UVMM module has been improved.
* A regression in the users/self module regarding saving
  unset properties with default values has been addressed.
* The udm module flavors are requiring a minimal set of
  allowed UMC commands now to be visible in the UMC.
* A widget has been moved to the common library.